Patent Literatures 1 to 2 disclose radiation detectors that increase the efficiency for detecting scintillation light, and improve the sharpness of radiation images. Non-Patent Literature 1 discloses a detector to be used for a PET device. The efficiency for detecting scintillation light means the efficiency for collecting scintillation light, and means the rate of scintillation light that could be captured by a photodetector out of scintillation light generated in a scintillator.
The radiation detector of Patent Literature 1 has a configuration for which a solid-state photodetector is laminated between two scintillators. X-rays transmitted through a subject are irradiated onto the radiation detector. One scintillator emits visible light of an intensity according to the intensity of the irradiated X-rays. The visible light is converted into an image signal. X-rays that have not been converted to visible light are transmitted through the solid-state photodetector to reach the other scintillator. The other scintillator emits visible light of an intensity according to the intensity of the X-rays reached. The visible light is converted into an image signal by the respective solid-state photodetector elements.
The radiation detector of Patent Literature 2 has a configuration for which a planar scintillator is laminated sandwiched from the front and back between two solid-state photodetectors. X-rays transmitted through a subject are irradiated onto the radiation detector. The X-rays are transmitted through the solid-state photodetector and irradiated onto the scintillator. The scintillator emits visible light of an intensity according to the intensity of the irradiated X-rays. Visible light that is emitted to the side on which X-rays have been made incident is converted into an image signal by one solid-state photodetector. Visible light that is emitted in an opposite direction thereto is converted into an image signal by the other solid-state photodetector.
Patent Literature 3 discloses an imaging device capable of performing at high resolution imaging for scintillation light that is emitted in a scintillator. The imaging device of Patent Literature 3 includes a scintillator that emits scintillation light in response to incident energy beams and a first CCD section and a second CCD section that take an image by the scintillation light. The first CCD section and the second CCD section are disposed so that their respective imaging units face each other, and the scintillator is disposed so as to be sandwiched between the two imaging units and be overlapped in a plane view with these two imaging units.
The radiation detector of Patent Literature 4 has a scintillator on which X-rays are incident and a solid-state photodetector which detects scintillation light that is emitted from this scintillator. The scintillator emits visible light of an intensity according to the intensity of the X-rays. The visible light is photoelectrically converted into an image signal.
Patent Literature 5 discloses a positron CT device that is capable of making a positron distribution into an image uniformly and at high resolution across the entire visual field by preventing deterioration in position resolution in a peripheral visual field. For the positron CT device of Patent Literature 5, a plurality of detector units each consisting of a scintillator bundle for which columnar scintillator elements are bundled and position detection-type photodetectors coupled to both ends of the scintillator bundle are arranged in a ring shape, and a rough ground portion is provided at a part of a surface other than joint surfaces of each scintillator element with the photodetectors.
Patent Literature 6 discloses a radiation detector that is capable of efficiently guiding light generated in a scintillator to a photodetector. For the radiation detector of Patent Literature 6, the scintillator has a light output surface formed in a wedge shape, and a light input surface of a light guide is formed in a V-shape that receives the wedge shape.